1. Field of the Disclosure
The present disclosure relates to a blocking filter, and more particularly to a blocking filter for power line communication.
2. Discussion of the Related Art
The information disclosed in this Discussion of the Related Art section is only for enhancement of understanding of the general background of the present disclosure and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Generally, a PLC (Power Line Communication) is a method of transmitting data (e.g., voice sound, data signal) by superimposing a PLC signal (2 to 30 MHz) having a high frequency, being an information signal, on a signal having a commercial frequency (50 to 60 Hz) transmitted to an indoor or outdoor high voltage or low voltage power line.
PLC (networks) can advantageously utilize existing power lines, dispensing with additional installation of communication lines, to reduce investment cost and to facilitate computer networking (or networking of other appliances such as audio/video equipment) using a simple connection of plugs. In addition to the abovementioned advantage, concomitant with desire to intelligently control consumer facilities and development of information devices, the PLC is briskly applied to such fields as AMR (Automatic Meter Reading) system, home network system, AMI (Advanced Metering Infrastructure) system and factory automation.
In PLC system, lots of branches (equipment) exist on the PLC to disadvantageously cause signal loss and inroad of noise. In order to overcome this restriction, a blocking filter may be required to prevent generation of unnecessary signal flow in PLC frequency band, e.g., flow of PLC communication signal into the PLC branches, prevention of generation of noise caused by abnormal power facilities, prevention of flow of unnecessary signal due to inflow of noise generated by neighboring equipment, or to minimize mutual interference of PLC signals in individual networks using respectively different PLC technologies.
For example, use of a blocking filter is recommended in order to prevent high indoor noise and low impedance in AMR system from influencing on outdoor PLC environments, and use of a blocking filter is required to make a physical difference among neighboring networks in home network system.
Meanwhile, the abovementioned blocking filter is generally installed after a consumer's utility meter, and since the AMI system uses the PLC from a concentrator to consumer's utility meter and ESI (Energy Service Interface), a PLC signal may not reach the ESI since an indoor ESI is positioned after the blocking filter, in consideration of a general installation position of the blocking filter.
As noted above, since applicability or installed position of the block filter is changed according to types of systems using the PLC, the blocking filter must be repeatedly installed or removed due to changes in PLC services to increase inconveniences to a power consumer or a power provider.